Aviation Mechanics Bulletin 1995

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November–December 1995

To determine which human factors influence aircraft-inspection reliability, the U.K. Civil Aviation Authority (CAA) evaluated the performances of qualified inspectors working for six days under
controlled environmental conditions. The study was conducted as part of the joint U.S. Federal Aviation Administration (FAA)/CAA Aging Aircraft Inspection Program.

September–October 1995

In the United States, the U.S. Occupational Safety and Health Administration (OSHA) is the government agency that promulgates workplace safety regulations and provides over-sight to ensure compliance. Its publication OSHA Handbook for Small Businesses includes some of the strictest and most detailed workplace-safety checklists. Many of the items found in these checklists apply to aviation maintenance facilities anywhere in the world.

July–August 1995

A typical repair costs 50 percent to 80 percent less than replacement. And nearly half of all damaged cockpit windows can be repaired to a “like-new” condition. Relamination and other
repairs are feasible for transparencies used in most pressurized-cabin aircraft.

May–June 1995

More precise temperature-measurement devices have provided the aircraft technician with enhanced tools to perform diagnostic tests on static systems and operating equipment. Infrared (IR) thermographic devices are extremely accurate and easy to use. Rather than using a thermo-couple, or temperature-sensitive liquid as in the common thermometer, IR temperature measurement does not
require physical contact to provide accurate measurements.

March–April 1995

On March 1, 1994, a Northwest Airlines Boeing 747 arriving at New Tokyo International Airport, Narita, Japan, suffered a serious accident on roll-out after landing. The flight, touchdown and initial roll-out were routine. Reverse thrust was selected on all four engines, but when the flight crew moved the engine power levers out of reverse at about 90 knots, the No. 1 engine and pylon sagged, rotating about the midspar pylon-to-wing fittings, allowing the lower forward part of the nose cowl to contact the runway. The aircraft was stopped on a taxiway, with the front of the No. 1 engine contacting the ground. A large portion of the lower forward engine nose cowl had been ground away as it was dragged on the runway.

January–February 1995

Aircraft owners, pilots and overhaulers take a collective deep breath as they approach one of the most critical points of an engine’s life — break-in. A new engine or freshly overhauled engine is an expensive investment, with the first few hours of engine operation determining how well it will operate until TBO (time before overhaul). Improper break-in can lead to cylinder problems or even a costly engine failure which could contribute to an incident or accident.